Provided are compositions and methods for use in selectively killing one or more of C. perfringens, C. sordelli and C. histolyticum. The compositions include lysin PlyCP025, as well as catalytically active fragments thereof, and variants thereof that retain killing activity. Methods for reducing one or more of C. perfringens, C. sordelli or C. histolyticum bacteria are provide and involve contacting such bacteria with a composition that contains PlyCP025 or an enzymatically active fragment or variant thereof, which can be provided as recombinant polypeptides. The composition and methods are useful for human and veterinary purposes. Diagnostic approaches are also included by contacting a sample obtained or derived from an animal, with a recombinant polypeptide, and detecting binding of the polypeptide to bacteria in the sample if said bacteria that are bound to the polypeptide are present in the sample. The polypeptide may thus be detectably labeled to produce a detectable signal.